Method for producing made-to-measure orthopaedic shoes

ABSTRACT

The invention relates to a method for producing made-to-measure orthopaedic shoes consisting in three-dimensionally scanning the loaded foot of a patient. Measured data are taken by scanning, recorded in a computer and processed in such a way that a three-dimensional image of the foot is obtained. Afterwards, an X-ray image of the patient foot is superposed on said calculated image. The measured data obtained by the scanning makes it possible to control machining devices for the automated manufacture of lasts, shanks, soles, uppers and pinching

The present invention relates to a method for producing made-to-measure orthopedic shoes.

In contrast to the industrial production of standard shoes for daily use, made-to-measure orthopedic shoes—as the name already says—can only be produced, up to the present, in complicated individual production by a skilled craftsman, whereby according to this old method, a very specific, predetermined sequence has to be followed. This begins with measuring the foot, using a tape measure, whereby measurement inaccuracies can already occur here, which continue and multiply in the subsequent process. After the foot has been measured, a corresponding last is produced. Subsequently, the individual sole is produced. Then, using a base model that has been produced by hand, the material for the upper is cut to size and then sewn. After the insole has been applied, the upper is placed onto the last and tacked in place. Then the lasted upper is glued in place and then the tacks are removed again. This method of procedure is very time-consuming. In order to complete this shoe, the sole is then attached.

In contrast, the invention is based on the task of being able to produce such made-to-measure shoes, which are normally produced by manual labor, more quickly and with greater precision, by means of automated methods.

By means of shortening the production time, there are also significant medical advantages. The physician can take his/her medical healing method to the outer limit, and can assure provision of a shoe only at the conclusion of an overall treatment. This can be explained using the example of a heel fracture and a shoe supplied for this fracture. Usually, what was done until now was that a measure has to be taken during the eighth week, or during the ninth week, at the latest, to produce orthopedic shoes, since the medical healing process is completed twelve weeks after the heel bone fracture, so that the patient can receive his/her shoe during the twelfth week. Using the new method, the shoe can be produced as late as during the eleventh week, which has the advantage that up to that time, the shape of the foot has positively changed as a result of the anti-swelling measures, etc., and therefore the fit of the shoe is, of course, significantly better than in the case of a shoe production time that now takes three to four weeks.

The new method is characterized in that the foot of the patient is photographically scanned in three dimensions, in the loaded state, that data determined by the scan are stored in a computer and processed to produce a three-dimensional image of the foot, that an X-ray image of the patient's foot is superimposed on this calculated image, and that processing machines for automated production of lasts, i.e. the sole, the upper, for lasting and for base construction are controlled by means of the measurement data obtained by means of the scan, taking into consideration the default values of the X-ray image that has been superimposed.

Medically, there is a significant advantage, since particular features of ankle anatomy can be taken into consideration by means of the particular features of scanning in the X-ray image, in a form that was not known until now.

Even calluses or other soft tissue changes can be taken into consideration, so that no pressure points occur. The problems of hammertoes and the height of the toecap (if a work shoe is to be made) can be recognized directly on the computer here, and can be discussed, if necessary. In the past, the shoes were made, the patient then only noticed the pressure points when trying them on, and they could be changed only with difficulty and with a great expenditure of time. With the new shoe production method, it can already be determined on the computer, in advance, whether the predetermined steel caps and the toes, for example, even fit together. This results in a significant cost reduction in advance. Because the foot is appropriately documented from below by means of the three-dimensional representation, specifically while there is a load (if necessary, a partial load) on the foot, any deformations that occur under a load can be taken into consideration. An equalization between the last and the dimensions of the foot is also allowed by the three-dimensional production of the last, and by the check of measurements (see below), and therefore the orthopedic shoe technology and the treating and prescribing physician can interact closely with one another, without negative influences being possible in any manner.

As is evident from the attached schematic diagram, the method according to the invention demonstrates significant variability. Proceeding from the scanning process and the measurement data determined by it, last construction, upper construction, and sole construction can begin in parallel. It is also possible to start with the base construction right after scanning, and this results in a very accurately produced shoe, for one thing, in view of the high level of measurement accuracy, which is produced, on the other hand, in a significantly shorter time than in the case of conventional methods.

In the following, the process sequence for producing a made-to-measure orthopedic shoe using the new method will be explained in an example.

The patient places the diseased or injured foot onto the glass foot plate of a photographic scanner that consists of five cameras, four of which are disposed in the corresponding corners, and the fifth on the bottom.

Since the detection zones of the individual cameras overlap, the data are processed in the computer in such a manner that a virtual image of the foot is calculated. The finished image now shows the foot silhouette with all its anatomical peculiarities.

The image can be viewed from all sides. As a particular feature of the invention, the X-ray image of the patient's foot is now superimposed on this 3D image, so that in this phase, particular features of the bones of the skeleton can be worked in and taken into consideration.

On the basis of the measurement data determined by means of the scanning process, the corresponding last design is not calculated by the computer; it can be modified in accordance with the peculiarities of the outer foot and the skeletal structure of the foot, at the most varied locations.

In the so-called dimension checking step, which shows the measurement data of the foot in a virtual form, a check of the individual measurement data takes place once again, if necessary also a check as compared with inspection data obtained by hand (old method).

The next step is the virtual intermediate comparison. Here, the last that has been calculated is compared, by the computer, with data of the foot. In other words, the measurement check is worked into the last, in order to see if the last agrees with the inner foot data. Specifically in this phase, as well, particular features that have been predetermined by means of orthopedic technology or medically, can be taken into consideration, and this is an absolute novelty.

Now, the leather cutouts for the upper are calculated from the calculated last, by means of computer, and again, this is also a virtual copy of the last.

In the design of the upper, the anatomical peculiarities of the foot are again taken into consideration, of course.

Cutting of the leather, using a CAD-controlled cutting table, on the basis of the measurement data stored in the computer, takes place with a precision that has not been achieved in practice until now. This cutting table cuts, perforates, and creates the markings for assembly of the upper, in completely automatic manner.

During assembly of the upper, the pieces of leather are put together, and the lining (or any cushioning parts) is/are also worked in. The leather is fitted with eyes and the other utensils that are typically necessary. For street shoes, the toecap is also worked in at the same time here.

What is new is the design of the last, including the subsequent sole, as a unit. This results in a more precisely fit assembly of the orthopedic shoe by means of machines. Therefore assembly of the shoe can already be started without first producing the sole, as in conventional production. Now, the lasts, and, independently in terms of time, the soles are milled on the basis of the computer data. The milling method used until now looks as follows. A single last was milled and subsequently cut open by means of a band saw and fixed in place by means of screws. The subdivision is necessary in order to remove the last from the shoe after it has been completed. In the case of the new method, several lasts are milled from a larger block. Depending on the size, up to five pairs in one work cycle. Likewise, the lasts are also already milled in divided form. This has two significant advantages. For one thing, the dimensional inaccuracy that occurs during subsequent separation is eliminated. When it is sawed apart with a band saw, the last loses dimension by the thickness of the saw blade. The second advantage will be explained in greater detail in the following paragraph. The milling process can occur on two machines at the same time, or on one machine, one after the other. A person skilled in the art will choose the usual materials for the last. A different selection of materials applies for the sole. Here, rubber-like material having different values of Shore hardness is selected; depending on the medical prescription, rigid inserts, semi-soft inserts, or soft inserts are selected. The sole is then furthermore covered with leather or other materials, in order to prepare it with regard to foot perspiration and the like, and for wearing comfort.

Because the milling machines are computer-controlled, there are significant advantages here also for the precision of production.

The fact that the last is first processed for the narrowest finished sole shape is also new in the case of the method according to the invention. But since the wishes of the patients vary, as do the prescriptions of the physicians, a variable configuration must be possible here, which is ensured in that plastic cover caps are set on, in order to arrive at wider last shapes. These cover caps are designed on the computer drawn up by a 3D printer. The calculated last is taken into consideration in the type and shape of the required cover cap, so that a plurality of different shapes is possible for configuring the shoe in the toecap region, by means of this type of method, without making the method itself more complicated in terms of time, or delaying it in terms of time. As was already mentioned above, the second significant advantage of milling the lasts in the divided form. Since the division is carried out in the computer and stored permanently, a new front part in the changed shape can be milled for the last in question at any time. Both methods—cover cap and alternating tip—are used, depending on the size of the changes. In this way, fast production of the basic lasts continues to be guaranteed.

Assignment of the individual last to the patient, in each instance, is assured by means of a chip. This means, in detail: The last, which was provided with an engraved identification number during the milling process, is now provided with a chip that can be read out, which can be read out and identified using a reading device. The computer recognizes the related patient in the network, on the basis of the identifier stored in the chip. Therefore the employee in question has all of the patient data as well as shoe production data that he/she requires available to him/her.

Now basting of the insoles to the last takes place. These insoles are already available in their final form, since they were designed in advance, in the computer, during comparison of the last shapes with the finished sole, and were cut on the cutting table. The same also holds true for the different rear caps.

Now the lasting process for the toecap region takes place by machine. The machine used is so variable that different lateral slanted problem solutions are possible. Teflon tapes are attached to the tip lasting machine. These lateral lasting tapes can be appropriately changed by the orthopedic shoe technician by means of specific technical defaults on the device, specifically independent of the individual shape, in order to achieve an adequate shape of the forefoot, i.e. the shoe. Since these tapes are so flexible that they resume their original shape after the load on them has ended, this technical device guarantees that shoes having the same shape can be processed, one directly behind the other, as can those having different forefoot shapes. This machine is able to process 200 pairs of shoes per day. A disadvantage of this lasting machine, which, however, at the same time proves to be a great advantage, is that because of the forces that the lasting machine exerts and that cannot be achieved manually, when all of the regions of the front blade components are lasted at the same time, the defects in the hide of which the leather cut-outs consist will result in destruction of the hide, i.e. of the upper. When working manually, it would be possible to even this out and take it into consideration accordingly. This means, on the one hand, that of course the hide is being handled gently, in this connection, but on the other hand, that it is possible to process low-quality material by hand, something that is not possible when using the lasting machine, so that here, the machine is certainly of higher value for quality assurance than manual lasting.

The heel region is produced in a separate heel lasting machine. This lasting machine functions according to the same principles as above. In the lasting process phases both for the front region and the rear region, the lining is first worked in, particularly for the heel and the heel cap, or any orthopedically required rear cap types, so that these can be worked in right with the lasting process. This is not the case if a steel cap is needed. For front blade lasting, it is required, at first, that the lining is lasted. Afterwards, the steel cap is worked over, and the front blade is lasted over it.

The lasting process is carried out by means of contact glue, in each instance, over both regions. Complicated tacking and subsequent removal of the tacks are therefore eliminated.

Any free, open regions of the upper that remain between the tips and the heel region can be attached using a side roll-in machine.

During base construction, the finished soles are applied, i.e. glued to the lasted region. In this phase, particular features in the sole construction are taken into consideration, such as a steel spring that is provided to ensure that the base has a certain strength in the rear region, as well as other orthopedic requirements, which are, of course, also predetermined by the physician.

A solid unit between the sole and the remaining structure of the shoe is guaranteed in a base press.

For final assembly, the cut soles are now inserted into the finished shoes.

Different special base presses guarantee a firm connection between the soles and the remaining structure of the shoe, because of their high contact pressure, which acts either on the sole side or laterally or also in combined manner. These work steps apply for made-to-measure orthopedic shoes of all kinds (work shoes, street shoes, house shoes, athletic shoes, etc.).

In summary, it must therefore be stated that by means of the scanning process of the foot the superimposition of the foot X-ray image, the computer has all the data available that are required to control the various processing machines and to produce a shoe that takes individual situations into account to an even higher degree than a shoe that was produced using the conventional, traditional method.

Before the actual production begins, all of the characteristics and properties of the accurately fitting shoe have therefore been determined. 

1. Method for producing made-to-measure orthopedic shoes, in which the foot of the patient is photographically scanned in three dimensions, in the loaded state, data determined by the scan are stored in a computer and processed to produce a three-dimensional image of the foot, an X-ray image of the patient's foot is superimposed on this calculated image, and processing machines for automated production of lasts, i.e. the sole, the upper, for lasting and for base construction are controlled by means of the measurement data obtained by means of the scan, taking into consideration the default values of the X-ray image that has been superimposed.
 2. Method according to claim 1, wherein the measurement data obtained by means of the scan are used to calculate a last design that is subsequently compared with the measurements of the scanned foot, and that any modifications of the design that are necessary are made.
 3. Method according to claim 1, wherein the last (last and sole as a compact unit) and the sole are produced parallel to one another, on the basis of the scanned measurement data.
 4. Method according to claim 3, wherein several pairs of lasts are milled from a block, at the same time, and that the lasts are equipped with an identification chip.
 5. Method according to claim 1, wherein the last is first worked to the narrowest finished sole shape, on the basis of the scanned measurement data, whereby individual patient foot shapes and medical defaults are taken into consideration for the front foot region by means of cover caps created by a 3D printer.
 6. Method according to claim 1, wherein lasts composed of individual modules, having alternating tips, are used.
 7. Method according to claim 1, wherein the front cap region is drawn around the last in an automatic lasting machine, taking into consideration the measurement data obtained by means of scanning, with uniform force over the circumference of the forefoot region, and attached.
 8. Method according to claim 1, wherein the heel region is also produced by means of a lasting machine.
 9. Method according to claim 7, wherein the toecap is first worked in, during the lasting process phases.
 10. Method according to claim 7, wherein during the lasting process, the upper is drawn around the last by machine, and attached.
 11. Method according to claim 1, wherein both the last and the sole are milled.
 12. Method according to claim 1, wherein during base construction, the finished sole is connected with the remaining structure of the shoe in a base press. 